Shutter for motion-picture projectors and cameras



Margh 4, 1930. A. M. OHAGEN ET AL SHUTTER FOR MOTION PICTURE PROJECTORS AND CAMERAS Filed Deq.'2l. 1927 AMEI'HELEEH. EIIIEI E175 Er Patented Mar 4, 1930 ARGHIBALD M. OHAGEN AND, GEORGE PATENT OFFICE c. BERGER, 6r rossrou, mm'mso'ra SHUTTER FOB MOTIOIT-PICTURE PBOJ'ECTORS AND CAMERAS Application filed December 21, 1927. Serial No. 241,617.

This invention relates to motion picture apparatus and .has special reference to the s utters of motion picture projecting Inachines and cameras. Heretofore, motion picture projecting machines have been equ pped with a-single shutter having a plurality of blades which are rapidly moved past the lens so asto alternately cut off the light from the screen and permit the light topassto the screen but such shutters have been objectionable for the reason that they permit flicker upon the screen which is tr ing upon the eyes of spectators and also etracts from the smooth effect of the pictures. It is the object of the present invention to provide a shutter mechanism by the use of which the light will be cut oif an admitted to the screen at shorter intervals than heretofore and will be shut off or admitted in such a manner that the flicker will be eliminated. The invention is illustrated in the accompanying drawing and will be hereinafter described, the novel features being particularly pointed out in the appended claims.

In the drawing: Figure 1 is a front'elevation of our improved shutter; v Fig. 2 is an edge elevation of the same, a portion of the projecting machine being indicated in a conventional manner, and

Fig. 3 is a view similar to Fig. 1 but showing a 'diflerentform of gearing. In'the drawing, the reference numeral 1 indicates a 1portion of'a motion picture pro- 'jecting mac ineand 2 designates the projecting lens which may be of any approved form. Disposed concentrically about the lens and spaced at equal distances apart are a series. of three shutter shafts 3, 4 and 5 upon each of which is secured a shutter 6, it being noted that the shutters are so disposed that they will overlap and are, therefore, arranged at different distances from the projecting machine in order that they may easily clear each other when in operation. At the same time, howevei', the shutters are arranged close enough together to avoidblurring by reason of the passage of light arouiid the edges of the shutters. At the outer extremity of each shutter shaft, there is secured a sprocket pinion 7 that three blades will simultaneously pass spread radially from the center of the lens and a sprocket chain 8 is trained around the several pinions so that the shutters will be rotated in the same direction and at equal speeds, the uppermost shutter shaft 3 being driven from the operating mechanism of the projecting apparatus in the usual manner. Each shutter consists of a hub member 9 and blades 10 radiatin from the hub member, four blades being 5 own in the drawing and being usually employed as givin the most satisfactory results. Each blade has its side edges diverging outwardly from the hub, as shown at 11, to a point about midway the length of the blade and then converging outwardly, as shown at 12, toward the outer end ofthe blade and the length of the blade is such that it may extend entirely across the lens and the point 13 where the diverging and converging edges meet will passv across the lens at the axis thereof.

lln Fig. 1, the shutters are shown in the position assumed when the blades are entering the field of the lens, and it will be noted across the lens and the angle 13 of each blade will follow an are passing throughthe axial center of thelens. The blades pass across the lens in converging paths beginning at points spaced equi-distantly about the pe-' riphery of the lens and the result is that'the light is cut oil from the lens from its periphery inwardly in a plurality of directions, the relatively inclined edges of the several blades causing the light to be cut off in a gradual but rapid manner instead of abruptly on lines radial to the lens or parallel. with a radius of the lens. As the blades leave the" lens, the light will be gradually although rapidly admitted-to the lens on'paths which instead of being admitted through one side portion of the edge and then gradually spreading over the lens to the opposite-side thereof. As a result of th's operation, the 9 light is cut off from the screen and admitted thereto at shorter intervals than heretofore and also in a more even manner than hereto-/' 3 fore so that the objectionable flicker is mini mized, if not entirely eliminated, and a more 100 pleasing effect is obtained in the production. blades being such that each blade in its travel The device is exceedingly simple and inexpasses entirely across the lens. pensive and may be readily. applied to exist- In testimony whereof we have aflixed our mg machines as well as to machines hereinsignatures. after manufactured. ARCHIBALD M. OHAGEN. [L 5.] 70 While we have shown sprocket gearing in GEORGE C. BERGER. [L 5.] Figs. 1 and 2 for rotating the shutters, other forms of gearing ma be employed, and spiral gearing is illustrated in Fig. 3. In Fig. 3, the drlving shaft is equipped with 7 a spiral pinion 21 and frame rods 22 extend between and provide outer bearings for all theashutter shafts, spiral pinions 23 being provided on the driven shutter shafts. The 15 frame rods 22 which diverge from the drivso ing shaft carry bearings 24 in which are journaled transmission shafts 25 each equipped at its ends with pinions 26 meshing with the reslpectively adjacent pinions 21, 23. 20 aving thus described the invention, we 85 claim: 1. A shutter mechanism for motion picture apparatus comprising three shutters arranged concentrically about the lens of the 26 apparatus and spaced equal distances apart 90 and each consisting of a hub member, and four blades radiating therefrom, the blades having their side edges diverging outwardly from the hub and then converging outwardly 30 to the end of the blade. I

2. A shutter mechanism for motion picture apparatus comprising three shutters arranged equi-distantly and concentrically about the lens of the apparatus, a shaft for Y each shutter, one shaft being a driving shaft, I

frame bars disposed in trlangular relation and connecting the driving shaft with both driven shafts and the driven shafts with each other, diverging transmission shafts M) mounted on the frame bars extending from 6 the driving shaft, and gearing at the ends of the transmission shafts connecting them with the respective shutter shafts whereby to rotate the shafts synchronously. 3. A shutter mechanism for motion pic- 9 ture apparatus comprising three shutters each having a blade arranged concentrically and symmetrically about the lens of the motion picture apparatus, the blade of each shutter having its side edges diverging outwardly to a point which travels across the center of the lens and then converging outwardly to the end of the blade, forming an obtuse angle.

' 4. A shutter mechanism for motion picture apparatus comprising three shutters each having a plurality of blades arranged concentrically and symmetrically about the I oo lens of the motion picture apparatus, the 126 blades of each shutter having their side edges diverging outwardly to a point which travels "across the center of the lens and then converging outwardly to the end of the blade, 55 forming an obtuse angle, the length of the 1 

